A surface light emitting apparatus for emitting light through a surface area has been used in various fields. Especially, the surface light emitting apparatus is used the most as a backlight, a signboard, and an advertisement board, and there is a very high possibility in that the surface light emitting apparatus will be applied as an interior lighting or lightings for other industries in the future.
According to the development of LED light sources, an application field of the surface light emitting apparatus has been expanded, and a size of the surface light emitting apparatus has been decreased and structures of the surface light emitting apparatus becomes various. The backlight using an LED light source is mainly used as a light source of a very thin LCD, and has a structure illustrated in FIG. 1. The conventional surface light emitting apparatus includes a light guide plate 110 having a scattering pattern and a light source bar 120 including LED light sources 122, and has a structure in which an optical signal is incident to a side surface of the light guide plate 110 and a surface light emission is generated in a direction vertical to the light guide plate 110 by a scattering pattern 130. The structure is used as an LED surface lighting or a backlight of an advertisement sheet.
FIG. 2 is a diagram illustrating a configuration of a signboard using LED light sources. The signboard has a similar structure to that of the backlight, however a scattering pattern 230 is not formed on an entire light guide plate 210, but rather is formed on a partial region of the light guide plate 210. The signboard is generally used as a display for transferring information, such as a telephone number, a price, a pattern and a phrase. Especially, signboards having various structures using the LED have been recently suggested, and an advertisement effect is obtained through a new function.
However, the conventional surface light emitting apparatus has a structure in which a plurality of LED light sources are arranged in one side surface or both side surfaces of the light guide plate. Accordingly, when a size of the light guide plate is increased, a large number of LED sources are required. Further, since a thick and hard acryl plate is used as the light guide plate, the light guide plate cannot be bent. Further, when the light guide plate is thin, strength of the light incident to the light guide plate from the LED light source is very small, so that there is a disadvantage in that it is difficult to realistically implement the surface light emitting apparatus. The aforementioned disadvantages deteriorate the applicability of the surface light emitting apparatus to various fields, such as a surface light source, a signboard and a banner, using a light.